Generally, a refrigerator accounts for a high rate of power consumption at home, and it is strongly required to reduce the power consumption as much as possible. In order for this, a refrigerator is proposed, which allows a power-saving operation using a light sensor or a door opening and closing detection switch.
For example, in a case where the light sensor detects that an external illuminance is equal to or higher than a predetermined illuminance, the refrigerator performs an ordinary operation. On the other hand, when the light sensor detects that the external illuminance is lower than a predetermined illuminance, the refrigerator determines that the customer has gone to bed and there is almost no possibility of opening the door of the refrigerator, and thus, performs a power-saving operation in which the refrigerator is operated by a power lower than the ordinary power, that is an energy-saving operation (for example, refer to PTL 1).
FIG. 24 is a flow chart for explaining a control of a refrigerator in the related art.
As illustrated in FIG. 24, when a switch for the energy-saving operation is pressed, the light sensor detects (S401) the illuminance around the front side of the refrigerator and calculates an illuminance changing rate (S402).
Next, the light sensor determines whether or not the changing rate is an increasing rate, and whether or not the changing rate is equal to or higher than a pre-set value, for example, equal to or higher than 150 lux/sec (S403). In a case where the changing rate is equal to or higher than the pre-set value, the ordinary operation is performed (S404), and in a case where the changing rate is not equal to or higher than the pre-set value, an illuminance decreasing rate is determined whether or not to be equal to or higher than the pre-set value (S405). In a case where the decreasing rate is equal to or higher than the pre-set value, the power-saving operation is performed (S406), and in a case where the decreasing rate is not equal to or higher than the pre-set value, the process returns to S401 and the illuminance detection is performed again.
By the refrigerator in the related art like this, it is possible to perform the power-saving operation that is the energy-saving operation not only in the night time but also in a case of dimmed lighting. Therefore, it is possible to perform an effective energy-saving operation.
On the other hand, in recent years, a power shortage due to the stoppage of the nuclear power plant resulting from a safety review has come to be a concern. For this reason, the power-saving consciousness of the user has extremely increased.
From this point of view, considering the method of using various electric apparatuses such as a refrigerator, the user has also come to take a power-saving action such that the electric apparatus performs a power-saving operation as much as possible. In the refrigerator also, in addition to an automatic energy-saving operation performed by the refrigerator itself, for example, the consciousness of aggressively performing the power-saving by decreasing consciously the frequency of door opening and closing has started in the user.
As described above, supporting the power-saving consciousness of the user for an aggressive power-saving action of the user himself has become a problem. In order to solve this problem, a refrigerator is proposed, in which an electricity bill or the amount of power consumption is displayed, or the frequency of door opening and closing of the storage room is displayed on a display unit of the refrigerator.
However, any of such displays are only the displays of the amount of power already consumed by the refrigerator. That is, it is not possible to know to what extent the energy-saving operation function of the refrigerator is working, thereby the energy-saving being achieved. For this reason, it is not easy for the user to take a power-saving action for increasing the rate of energy-saving operation performed by the refrigerator itself, and there is a problem in improving the degree of power saving in collaboration between the refrigerator and the user.